Electrical control



March .8, 1938.

c. F. WARRICK ELECTRICAL CONTROL Filed lay 11, 1935 K W e 5 z 0% xm m; m mm .m 1 I Y W 6 57 01 8 8 9 o d. LIN/HF Ill a 2 fl o I, 7 m u M 34. 6 n 1. u

Patented Man-8, 1938 UNITED STATES PATENT orrlcs Bender Warrick Corporation, a corporation of Michigan Application May 11, 1935,

2 Claims.

This invention relates to an electrical control device and it has to do. especially with a device involving electrical circuits and switching mechanism for starting and stopping the operations of a condition changing mechanism with a range of time or range of variable conditions between the functions of starting and stopping or stopping and starting the condition changing device as the case may be.

The controlling device is one especially useful for controlling conductive liquid levels within certain ranges, and while the invention is not limited to use of controlling conductive liquid level, yet the device as shown herein is associated with means for controlling conductive liquid level. The general objectof the invention is the pro-' vision of an electrical control capable of what might be stated as universal use, in other words capable of use with any number of varying kinds of liquids so long as electrical current may be conducted through the liquid, and for starting and stopping mechanism, such as a pump, injector or the like, to vary the liquid level, and wherein there is any desired substantial range of liquid level between such starting and stopping, to the end that the mechanism is set into operation only at relatively infrequent intervals.

Fig. 1 is a view showing diagrammatically the electrical circuit arrangement and illustrating the mechanical means of a control device for governing the operation of pumping water out of a tank.

Pig. 2 is a similar view illustrating the arrangement where a high water level is to be maintained in a container.

The invention preferably employs the electrical control system covered in my Patent No. 1,979,127 of October 30, 1934, which, however, is combined herein with additional circuits and mechanism forcontro'lling the range or time interval. The device, as shown, comprises what may be termed an "A" frame or magnetic core I, having a cross piece 2, another cross piece 3 and legs 4, which constitute magnetic poles. A primary electrical circuit isillustratedat 5 to which a coil 6 is connected substantially permanently in-the sense that the coil 8 is energized all the while the device is installed for operation' The primary circuit,-

as shown in Fig. 1, runs to an electric motor I for operating a pump 1, and the circuit to the motoris opened or closed by aswitch having contacts I. A reactance or choking coil i0 is wound around the cross as at ii and its opposite, end connected by a conductor 12 to an electrode it in the tank It. A conductor it connects an electrode It to a bar 3. This may be grounded Detroit, Mich,

Serial No. 21,013 (01. 103-26) contact ii. A movable switching arm it is associated with the contact I1.

An armature is illustrated at 20 which may be acted upon by a spring 2i for holding the same away from the poles, and this armature is pivoted at 22 and carries an arm 23 with a switch or bridging member 24. In the present form shown the switching arm I8 is a spring arm tensioned toward the contact i1, and a strut 25 is positioned between the arm 23 and switching member l8 so that the spring 2i, in swinging the armature and arm 23 counterclockwise, shifts the switching arm l8 away from the contact II.

The construction for mounting the electrodes in the tank may comprise any suitable arrangement and, as shown herein, the two electrodes are mounted on an insulating piece 26 which may seal the tank.

This control device is designed particularly for use with alternating current, and in this regard the use of alternating current eliminates the electrolytic action which would otherwise be set up within the container by the use of direct current. In considering the operation of the device let it first be assumed that the liquid in the tank is at low level below the lower end of the electrode IS. The coil 8 being constantly energized is continuously setting up alternating magnetic flux. The cross bar 3 constitutes a shunt for the flux with the result that most of the flux passes in a path across the shunt 3. Of course, some flux may leak across the poles l, but this is insufllcient to attract the armature. Accordingly, the motor circuit is broken at the contacts 8. The tank H may be regarded as a sump tank or similar device, and the water therein or other liquid gradually fills contacts with the electrode it no action takes place, since the circuit for the electrode i6 is broken by the arm l8. As thewater rises and makes contact with the electrode l3, a circuit is completed through the reactance coil i0. Electrical current is induced in the circuit of the coil iii, and the eifect of this current is to set up a magnetic reactance to the flow of the magnetic flux through the shunt 3. Accordingly, the flux set up by the coil 8 seeks another path, and this path is across the poles and armature. The flux,

then, in seeking the path across the poles, is strong enough to attract the armature, and the same is shifted to its dotted line position. This closes the motor circuit by means of the switch It and'at the same time the spring arm it makes contact at IT. The motor now begins to operate to pump the water out of the tank it. The water it. As the water rises and will first recede from electrode l3 and continue, since the circuit for the reactance coil is completed through the contact I! and switch member l8. This constitutes a holding circuit. However, as soon as the water recedes from the electrode it the circuit for the choking coil is broken, with the result that the shunt is no longer choked by the reactive action and the magnetic flux set up by the coil 6 passes through the shunt and the armature drops back to its full line position. 'I'his breaks the motor circuit which discontinues operation, and likewise breaks the contact at I! and i 8. No further operationwill take place until the water or other liquid again rises to the point where the same engages with electrode l3.

In Fig. 2 the tank 30 represents any sort of a container, as for example a boiler or the like or other receptacle, into which water or other liquid is to be pumped or injected to maintain the level within certain ranges. The various elements in Fig. 2 are substantially the same as those in Fig. 1, and the same reference characters are applied to most of them. The electrodes l3a and l6a are selected with the desired diflerential in length to determine the range. In this form theswltch for'the main circuit is reversed. When the liquid level is below electrode Ilia, the circuit for the reactance coil is broken, the flux finds its path across the shunt, the armature drops'to the full line position, as shown in Fig. 2, and the circuit to the motor is closed. The motor and pump in Fig. 2 are representative of any device for discharging liquid into the tank 30. With the starting of the motor the liquid is pumped intothe tank and as the liquid rises around electrodes in nothinghappens .until the liquid comes into contact with electrode I 3a, making the circuit for the reactance coil, and the same chokes the shunt by reactive action causing the flux, set up by the coil 6, to seek a path across the poles, and the armature is attracted to break the circuit for the motor. At this time switch arm It makes contact with I! and the holding circuit is closed. This idle condition now maintains as the liquid level recedes to a point below the electrode Ilia at which time the circuit for the reactance coil is broken, the flux seeking a path across the shunt, the armature dropping away from the poles, and the motor begins functioning to bring the liquid level up.

This device is capable of use with most any conductive liquid, although the conductivity thereof may vary. When we refer to the conductivity of a liquid,; -water is included since water generally encountered has suflicient impurities therein to conduct electricity. The entire impedance coil is effective to choke the shunt during the entire range. In other words, the impedance coil is arranged to sufliciently choke the shunt so that the armature will be lifted magnetically by the poles. Since the force is sufficient to lift the armature, it is more than sufficient to hold it positioned once it has been drawn to the poles, and this force is substantially maintained without variation, while the water is receding, for example, along the electrode l6a or in the form shown in Fig. 2, while the liquid is rising along the electrode l6. Of course,'there is some slight variation in the line resistance due to variation in the area or surface of the electrodes submerged in the water, but this does not interfere with the use of the device with various kinds of conductive liquids. This sort of structure is diflerentiated from an arrangement where an impedance coil has certain windings for attracting the armature and a less number of windtainer within a range and wherein the container is equipped with a pair of insulated electrodes for contact with the liquid, one of which is relatively low in the liquid, and the other of which is located relatively high in the container and wherein there is liquidflow means operable for changing the liquid level in the container, comprising in combination,.a coil for connection to a source of alternating current for substantially continuously setting up alternating magnetic flux, a shunt for the flux, a controlling coil for choking the shunt, an armature movable to con- .trol the starting and stopping of the means for causing flow of the liquid, which is attracted by the flux when the second coil chokes the shunt and which is substantially unaffected by the flux when the controlling coil does not choke the shunt, a conductor connecting the high electrode directly to one end of the controlling coil, a second conductor connecting the low electrode to the said one end of the coil, means for completing acircuit through the coil to the liquid, a mechanical switch in the conductor between the low electrode and the coil, and means operatively connecting the switch and armature whereby armature movement opens and closes the switch.

2. An apparatus for electrically controlling the level of an electrical conducting liquid in a container within a range and wherein the container is equipped with two electrodes which contact with the liquid, one of which is relatively low in the-liquid, and the other of which is located relatively high in the container, and wherein there is a pump for pumping liquid to change the level in the container comprising in combination, electrical means for operating the pump, a switch for closing and opening the electrical circuit for said means, a coil for connection to a source of alternating current for substantially continuously setting up alternating magnetic flux, a shunt for the flux, a controlling coil for choking the shunt,

an armature movable to open and close said switch and upon which the flux is effective when the shunt is choked and substantially ineflective when the shunt is not choked, a conductor connecting the high electrode with one end of the choking coil, a second conductor connecting the lowelectrode to said one end of the coil, a mechanical switch in the second conductor, means for completing a circuit through the coil to the container, and means operatively connecting the armature and said second named switch to operate the same.

CHARLES F. WARRICK. 

